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Changes for page Sensor Module

Last modified by Heimir Thordarson on 2026/07/05 12:56
From version 58.2
edited by Heimir Thordarson
on 2026/02/09 20:01
Change comment: There is no comment for this version
To version 49.1
edited by Heimir Thordarson
on 2026/01/27 17:57
Change comment: There is no comment for this version

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5 5  Voltage divider Inputs = 2
6 6  3V3 Thermistor Inputs = 7
7 7  5V Pressure Inputs = 4
8 -Communication Protocol = CAN FD
9 -Max Data rate = 1 Mbps
10 -
11 11  {{/wikibox}}
12 12  
13 -= Table of Contents =
14 -
15 15  {{content}}
16 16  {{content}}
17 17  {{content}}
18 -{{toc reference="Electrical.Sensor Module.WebHome"/}}
13 +{{toc/}}
14 +
15 +
19 19  {{/content}}
20 20  {{/content}}
21 21  {{/content}}
22 22  
20 += =
21 +
23 23  = Description =
24 24  
25 25  The Sensor module is designed to measure any extra analog signals rear of the firewall. For AR26, the module is designed to measure two suspension displacement sensors, two oil temperature, four water pressure, four water temperature, and one air temperature sensor. All of the measurements are then transmitted to a CAN network, which there are two of.
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28 28  
29 29  In the following section, how the sensor module is connected will be covered. The connector for the sensor module is a [[High-Density d'sub-44>>https://www.te.com/en/product-2311770-1.html]] which is directly solderen onto the circuit board. The plug needed for this system is the [[204517-3>>doc:Sandbox.TestPage3]], which uses crimps instead of solder cups which is common for the dsub connectors
30 30  
31 -[[image:AR26_ASM pinout.png||height="287" width="616"]]
30 +[[image:AR26_ASM pinout.png||height="214" width="457"]]
32 32  
33 33  In the figure above, the pinout shows how the pins are divided. Each box shows which pins belong together for each usecase, where the red box is the power input. Yellow boxes are for each canbus network, while the green box is for each sensor used in AR26.
34 34  
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107 107  * {{mathjax}}\(\beta\){{/mathjax}} = material constant that defines the steepness of its resistance-temperature curve between two temperature points, usually 25/85 degrees celsius. In this case it is 3694 //**K.**//
108 108  * {{mathjax}}\(T_0\){{/mathjax}} = The test temperature at which the thermistor is 10k {{mathjax}}\(\Omega\){{/mathjax}}, which in this case is 25 degrees celsius.
109 109  * {{mathjax}}\(R_0\){{/mathjax}} = The resistance of the thermistor when it is 25 degrees celsius.
110 -* {{mathjax}}\(R_T\){{/mathjax}} = The live resistance of the thermistor.
109 +* {{mathjax}}\(R_T\){{/mathjax}} = The current resistance of the thermistor.
111 111  
112 112  === Filtering ===
113 113  
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161 161  
162 162  The sensors output latency can be expected to be a lot shorter than the air temperature sensor as the sensor is just a variable sensor based on placement. The limiting factor for the system which uses this information is the CAN-BUS messages from the inverters which send the information each 6.25 milliseconds. This means that the cut-off frequency cannot be any lower than 160 Hz, which will make the same type of low pass filter from the air temperature sensor acceptable with a cut-off frequency of 1591 Hz.
163 163  
164 -== Gearbox Temperature Sensor ==
163 +== Cooling Sensors ==
165 165  
166 -The gearbox Temperature Sensor for AR26 will be the [[GAG10K3976B1>>https://www.te.com/en/product-GAG10K3976B1.html]], a NTC temperature probe which will be installed into a generic M5 bolt which is mounted on the upright in the wheel assembly. The thermistor will be connected in a voltage divider configuration where the thermistor is in the lower position so that the voltage lowers when the temperature increases.
167 -
168 -[[image:Oil_Temp_schematic.png||height="271" width="632"]]
169 -
170 -Knowing the beta constant of the thermistor, the equation for the temperature based on the voltage measured by the ADC inside microcontroller can be derived.
171 -
172 -(% style="font-size: 1.5em;" %)
173 -(((
174 -{{mathjax}}
175 -$$
176 -R_T = R_f \frac{V_{out}}{V_{in} - V_{out}}
177 -$$
178 -{{/mathjax}}
179 -)))
180 -
181 -Where:
182 -
183 -* {{mathjax}}\(R_f\){{/mathjax}} = The upper resistor in the voltage divider which stays fixed, which in this case is 1k {{mathjax}}\(\Omega\){{/mathjax}}
184 -* {{mathjax}}\(V_{out}\){{/mathjax}} = The voltage over the thermistor, and the voltage that the microcontroller will measure.
185 -* {{mathjax}}\(V_{in}\){{/mathjax}} = The supply voltage of the voltage divider, which in this case is a constant 3.3 {{mathjax}}\(V\){{/mathjax}}
186 -* {{mathjax}}\(R_T\){{/mathjax}} = Resistance of the thermistor
187 -
188 -Knowing this, the resistance of the thermistor can be added into the following equation. This will determine the temperature of the thermistor based on the known resistance and the beta value of the thermistor.
189 -
190 -(% style="font-size: 1.5em;" %)
191 -(((
192 -{{mathjax}}
193 -$$
194 -T = \frac{1}{\frac{1}{T_0} + \frac{1}{\beta} \ln\left(\frac{R_T}{R_0}\right)}
195 -$$
196 -{{/mathjax}}
197 -)))
198 -
199 -where:
200 -
201 -* {{mathjax}}\(\beta\){{/mathjax}} = material constant that defines the steepness of its resistance-temperature curve between two temperature points, usually 25/85 degrees celsius. In this case it is 3976 //**K.**//
202 -* {{mathjax}}\(T_0\){{/mathjax}} = The test temperature at which the thermistor is 10k {{mathjax}}\(\Omega\){{/mathjax}}, which in this case is 25 degrees celsius.
203 -* {{mathjax}}\(R_0\){{/mathjax}} = The resistance of the thermistor when it is 25 degrees celsius.
204 -* {{mathjax}}\(R_T\){{/mathjax}} = The live resistance of the thermistor.
205 -
206 -=== Filtering ===
207 -
208 -
165 +The cooling sensors for the AR26 can is the
Oil_Temp_schematic.png
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